Anaesthesia: Premed and Induction practicals Flashcards
What are the aims of premedication?
Relieve patient anxiety
facilitate handling of patient
Provide analgesia
Provide muscle relaxation
For certain procedures/interventions
Smooth induction
Smooth maintenance
Smooth recovery
Reduce dose of induction/maintenance- MAC sparing
Anna is a 1 year old pug
She is due to have an ovariohysterectomy
Clinical examination: loud URT noise, otherwise normal
No other abnormalities on history
Last fed at midnight
What do you need to consider about signalment in general and specifically to Anna?
Age: early neutering
Breed
Temperament
Anna specifically: BOAS, stenotic nares, long soft pallet, thick tongue, hypoplastic trachea, laryngeal collapse, increased risk of regurgiation
Anna is a 1 year old pug
She is due to have an ovariohysterectomy
Clinical examination: loud URT noise, otherwise normal
No other abnormalities on history
Last fed at midnight
You have the following opioids: Buprenorphine, Methadone, Butorphanol
Which of these would provide the best sedation, analgesia and what would be the best choice for Anna?
Sedation- butorphanol
Analgesia- Methadone
Anna- methadone for analgesia- risk of worsening panting but offset by analgesia offered
Anna is a 1 year old pug
She is due to have an ovariohysterectomy
Clinical examination: loud URT noise, otherwise normal
No other abnormalities on history
Last fed at midnight
You have acepromazine and metomidine for sedation.
Which would provide the most reliabel sedation
Which would give the most muscle relaxation
What would you choose for Anna and why?
Most relibale sedation- metomidine
Most muscle relaxation- metomidine
Anna-
acepromazine less muscle relaxation which could have led to airway obstruction
Metomidine would give better analgesia and muscle relaxation but can lead to airway obstruction- should not be left unattended
Could use a combo
Anna is a 1 year old pug
She is due to have an ovariohysterectomy
Clinical examination: loud URT noise, otherwise normal
No other abnormalities on history
Last fed at midnight
What should you monitor carefully after premedicting Anna?
What should you be prepared to do rapidly if needed?
Monitor- breathing rate, effort, signs of paradoxical abdominal movement, excessive noise, cyanosis
Ready to induce GA and intubate trachea if URT obstruction occurs
Drake is a 9 year old Cob
He needs to be sedated so you can check his teeth
His owner francis wants to know if he needs a dental
Drake is clinically normal
Which class of sedative will you use?
You have the option of detomidine, romfidine and Xylazine, which and why?
For reliable sedation in adult horses you would use an alpha 2- agonist
Xylazine- short duration of effects
Romfidine- do not wan the horse to be ataxic if a gag is in use
Detomidine- longer examination
What are all the injectable induction agents in small animals?
Propofol
Alfaxalone
Ketamine
Tiletamine and zolaepam (uncommon)
Etomidate (uncommon)
What are all the co-inductio agents for small animals?
Ketamine
Benzodiazepines (diazepam or midazolam)
Opioids
Lidocaine
What are all the licensed injectable induction agents and co-induction agents for horses?
Injectable induction-
Ketamine
Thiopental
Co-induction agents
Benzodiazepines (diazepam or midazolam)
Guaiphenesin (GGE)
What is the only licensed food producing species injectable induction agent?
Ketamine
How are most injectable induction agents administered, when would this vary?
What other options are there for induction other then injection?
Most will be IV- in rare situations (field emergency) some can be administered IM (ketamine, midazolam, alfaxalone)
Inhalational agents- sevoflurane and isoflurane- most likely in small exotics where IM or IV difficult
What factors affect choice of induction agents?
Species
Breed
Size of animal
Temperament of animal
Route of administration
Licensing
Drug avalible
Cost
Environment- field/hospital
Procedure
Experience
What two co-induction factors often result in a smooth well controlled induction?
Ketamine and benzodiazepine- takes 60-90 seconds to cross BBB
What is wall induction and what are the benefits and disadvantages?
Wall induction is where the horse is positioned against a wall by several people in the induction box
Adv- more people means more chance of manipulation and correct position, more controlled induction-horse slides down wall to ground so may be useful if large distended viscus in abdomen
Dis- more human personnel risk, excellent communication and team work is required to coordinate and minimise risk of injury
Which has a faster onset of induction in horses thiopental or ketamine?
Thiopental 20-30 seconds
Ketamine 60-90 seconds
